With this spell, you place a magic ward on any object that casts a shadow. If the object is disturbed in any way that causes its shadow to shift (for instance, if it or a nearby light source is moved), a conjured Greater Shadow (Greater Shadow) emerges from the object’s shadow to attack the nearest creature within 100 ft (or attacking the first creature to get within range) and always gets a surprise round in combat. Anyone viewing the object with detect magic sees an aura of conjuration; true seeing reveals the spirit in the objects shadow, appearing as a vague, hazy silhouette, and anyone viewing with it through such means can similarly participate in a surprise round with the creature (possibly negating the surprise round entirely).

The shadow can be turned or destroyed as normal; otherwise, it remains for a number of rounds equal to your caster level, after which the spell’s duration ends. If the trapped object resides in a place that has no shadows, the trap does not trigger, although the spell remains in effect.